Polymer-matrix composites offer unique combinations of properties and are useful in a wide range of applications. Such composites may be fabricated utilizing either thermosetting or thermoplastic polymer matrix materials with a variety of particulate or fibrous fillers or reinforcements. It is generally advantageous to have strong adhesion between the polymer matrix material and the surfaces of the various particulate or fibrous substrates and there is considerable art related to substrate finishes and other treatments to optimize adhesion to polymer matrices. For example, in the production long-fiber reinforced composites, improved adhesion between the polymer matrix and the fiber reinforcement leads to increased material performance. Good adhesion is particularly important where failures are likely to occur by delamination or by other adhesive failure modes.
As described in, for example, U.S. Pat. Nos. 5,840,238, 6,310,121 and 6,525,125, polymers generated by olefin metathesis processes are attractive as composite matrix materials. Of particularly beneficial use are the polymers generated by the ring opening metathesis polymerization (ROMP) of cyclic olefins. The low viscosity of cyclic olefin resin formulations and the ability to control ROMP kinetics (e.g., U.S. Pat. Nos. 4,708,969 and 5,939,504) facilitate composite processing and manufacture, and the corrosion resistance and high toughness of ROMP polymers leads to good composite durability. Additionally, certain properties of ROMP polymers, e.g., mechanical strength and stiffness, heat distortion temperature and solvent resistance, can be further enhanced by crosslinking induced via thermal treatment (e.g., U.S. Pat. No. 4,902,560) or chemically by addition of peroxides (e.g., U.S. Pat. No. 5,728,785).
Commercially important ROMP resin formulations are generally based on readily available and inexpensive cyclic olefins such as dicyclopentadiene (DCPD), norbornenes, cyclooctadiene (COD) and various cycloalkenes. However, in contrast to traditional resin systems (e.g., epoxy, acrylate, urethane, and polyester resins) based on polar functional group chemistries, these nonpolar ROMP resins have poor intrinsic adhesion to the relatively polar surfaces of common carbon, glass, or mineral fillers and reinforcements. The addition of various silanes to such resin formulations for improvement of electrical and mechanical properties of ROMP polymers is described in U.S. Pat. Nos. 5,840,238, 6,001,909, and 7,339,006. Many widely used commercial silanes do not give optimal properties with ROMP polymers, however, and the greatest enhancements are only obtained when the silanes comprise groups with high metathesis activity (the relative reactivity of various metathesis active groups is described in J. Am. Chem. Soc., 2003, 125, 11360-11370).
Despite the advances achieved in the art, particularly in the properties of ROMP polymers and their associated applications, a continuing need therefore exists for further improvement in a number of areas, including the adhesion of ROMP compositions to substrate materials.